Struct ReliableStream 

pub struct ReliableStream { /* private fields */ }

Reliable stream mode with selective NACKs.

Features:

• Bounded retransmit window (32 packets)
• Selective NACKs (receiver-driven)
• Per-stream state
• Configurable RTO

Suitable for:

• Tool call results
• Guardrail decisions
• Session lifecycle events
• Error propagation

Implementations

impl ReliableStream

pub const DEFAULT_RTO: Duration

Default retransmit timeout

pub const DEFAULT_MAX_PENDING: usize = 32

Default max pending packets

pub const DEFAULT_MAX_RETRIES: u8 = 3

Default max retries

pub fn new() -> Self

Create a new reliable stream with default settings

pub fn with_settings(rto: Duration, max_pending: usize, max_retries: u8) -> Self

Create with custom settings

pub fn untracked_evictions(&self) -> u64

Number of unacknowledged packets that the stream evicted from its retransmit window because the window was full at on_send time. Each eviction means the caller’s syscall succeeded (bytes left this node) but the packet is no longer tracked for retransmit — a NACK can no longer recover it. A non-zero value indicates max_pending is undersized for the stream’s sustained throughput. Operators should size up or apply upstream backpressure rather than accepting silent loss.

pub fn set_rto(&mut self, rto: Duration)

Set the retransmit timeout

pub fn next_expected(&self) -> u64

Lowest sequence number we have not yet received. All sequences strictly below this value are contiguously received.

pub fn last_received_contiguous(&self) -> Option<u64>

Highest contiguously-received sequence number, or None if no packets have been received yet.

pub fn ack_seq(&self) -> u64

Get the current ack sequence (highest contiguously-received seq). Returns 0 when nothing has been received yet — callers that need to distinguish “received seq 0” from “received nothing” should use Self::last_received_contiguous instead.

pub fn on_ack(&mut self, acked: u64)

Process an acknowledgment. acked is the highest sequence the peer has contiguously received.

Trait Implementations

impl Debug for ReliableStream

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Default for ReliableStream

fn default() -> Self

Returns the “default value” for a type.

impl ReliabilityMode for ReliableStream

fn on_send(&mut self, descriptor: Arc<RetransmitDescriptor>)

Called when a packet is sent. The descriptor carries pre- encryption inputs so the retransmit path can rebuild a fresh-counter packet rather than replaying stale ciphertext.

fn on_receive(&mut self, seq: u64) -> bool

Called when a packet is received. Returns true if accepted.

fn needs_ack(&self) -> bool

Check if this mode requires acknowledgments

fn build_nack(&self) -> Option<NackPayload>

Build a NACK payload if there are missing sequences

fn on_nack(&mut self, nack: &NackPayload) -> Vec<Arc<RetransmitDescriptor>>

Process a received NACK and return descriptors for the caller to rebuild + dispatch. The returned Arc clones share the inner RetransmitDescriptor allocation; the caller bumps the refcount instead of deep-cloning the Vec<Bytes> of events.

fn get_timed_out(&mut self) -> Vec<Arc<RetransmitDescriptor>>

Get descriptors that need retransmission due to timeout. See Self::on_nack for the Arc-sharing contract.

fn has_pending(&self) -> bool

Check if there are unacknowledged packets

fn name(&self) -> &'static str

Get the name of this reliability mode